View Full Version : building a box, had a few ?'s

11-11-2005, 12:40 PM
going to build a slopt ported box for a pair of jl audio 10w7's
got box info off of Beerman's box caculator, just wanted to know if these #'s are good for a "SQL" box for my w7's.
box is for a 04 4-runner i listen to all kinds of music, looking for loud, very clean bass.

3.5 cu^ft net volume
32 htz tuning freq.
4.25" port width
61.625 square inches port area
39.75" port lenth
40w x 16t x 23d external dimensions

should i go smaller 3 cu^ft ?
lower or higher tuning point

i've built boxes before, i just want to get this one right......

any help would be appreciated :)


11-12-2005, 07:01 AM
assuming you are using 3/4" mdf board.

enclosure dimensions:
external dimensions= W:40" x H:16" x D:23"
internal dimensions = W:38.5" x H:14.5" x D:21.5" = 6.955cu ft internal volume

port dimensions:
port internal dimensions: H:14.5" x W:4.25" x L:40.39" port values used for calculating port tuning
port physical dimensions: H:14.5" x W:5" x L:39" = 1.636cu ft external volume " assuming your only adding one wall for the port and using 3 current wall of the enclosure" this value is use for port displacement inside the enclosure.

sub woofer displacement= .09cu ft x 2 subs = .18cu ft

not calculating bracing.

6.965cu ft enclosure internal volume
1.636cu ft port external dimensions that actually sit inside the enclosure.
.18cu ft total of both subwoofers displacement
5.149cu ft final volume of the enclosure
2.5745cu ft volume seen per sub.

a 5.149 enclosure with port internal dimensions: H:14.5" x W:4.25" x L:40.39"
will tune the box to, 26.18Hz F3:22.30Hz, freq cutoff:25Hz, with your peak being at
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no apparent port noise at 1000wrms.

that will be an SQ enclosure. since the freq response is pretty flat from 27Hz to 120Hz